Natural originate particles (such as naturally occurring aggregates, sand, crushed natural rock, e.g., basalt rock, etc), and artificially originated particles (such as artificially created aggregates, crushed building waste, industrial wastage, etc.) are used for various filling purposes. Many of these particles are hydrophilic in nature, tending to absorb and hold water to a certain degree.
High water content of filling materials is an undesirable quality in general. Since environmental water/humidity levels change dramatically, a smaller water content of filler is a positive quality contributing to a more stable surrounding.
Many attempts to create hydrophobic particles have been made in the past. However, none of the prior attempts achieved a desired combination of hydrophobic qualities, manufacturing ease and low cost final product to enable extensive use of such products.
Chinese Patent Specification CN1124755 describes a granular, waterproof and insulating material for building, having a granularity less than 0.8 mm, and which is made up of ordinary fine sand or other granular material and a waxy substance as a hydrophobic agent through mixing while heating to 100–130° C. for 10–30 min followed by cooling, and features low cost, no toxicity and no environmental pollution.
Chinese Patent Specification CN124755 provides three examples of carrying out this process, all of them with a single wax. In one example, the main substance, fine yellow sand, is taken from the Tenger desert. A diameter of ≦0.6 mm is selected and paraffin wax fragments are used to obtain the following weight ratio: yellow sand 96%; paraffin wax 4%. These are fed together into the stirrer, heated to 110° C., and stirred for 15 minutes. The resulting material is discharged and cooled to form the finished product. In a second example, the ratio is yellow sand 98% and paraffin wax 2%. In a third example, the ratio is talcum powder 96% and paraffin wax 4%.